Provide example devcontainer config for mdns and USB passthrough

[linkedupbits]

What does this implement/fix?

This adds commented-out configuration for the devcontainer.json to enable mdns discovery of devices and local usb serial access. This makes using a devcontainer much easier when developing components.
Un-commenting the example code and rebuilding the container within VS Code is all that is required.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Test Environment

• ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (0cbc06a) 53.69% compared to head (586ecb4) 53.69%.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #6094   +/-   ##
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  Coverage   53.69%   53.69%           
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  Files          50       50           
  Lines        9398     9398           
  Branches     1652     1652           
=======================================
  Hits         5046     5046           
  Misses       4053     4053           
  Partials      299      299           

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